Apps I've found useful. Most are free - I tend to look for free apps. I am Deaf and look for apps I can access without sound being necessary. I also look for apps that students either must use to create and show their learning, or is minds-on.

Language:
FrameArtist - Helps you create amazing photo arts by combining your photos in a very easy way and share via Facebook, Instagram,
Twitter, Flickr, Picasa, Tumblr, eMail, and messengers.
Kidblog - Teachers can monitor blog activity and moderate comments and posts. Students can easily upload photos and videos from their
iOS device.
LiveBinders - Gives quick access to your LiveBinders.com account. Integrate a variety of Web content into virtual 3-Ring binders.
Phonto - Simple application that allows you to add text to pictures.
PhotoCard Lite - Postcard app.
Pic Collage - Arrange photos into frames or get create with freeform collages, cutouts, filters, borders, stickers and text.
ScribbleMyStory - Targets ages 3-7, book and art creation platform where kids can imagine, create, and share what they make.
Skitch - use to mark up a pdf, annotate a photo, or draw something new. Has arrows, stamps, text, shapes, and more.
Snipbase - fast beautiful shopping lists, or any list made up of photos - when you touch the picture a green check mark shows it is done.
StoryKit - Create an electric storybook. Write text, add drawing or picture, layout the elements of your story.
Trading Cards - From ReadWriteThink. Create trading cards to share your understanding of a topic.
QCards for Quizlet - Syncs to Quizlet. Create new sets of flashcards or study from existing ones.

Math:
Geoboard, by The Math Learning Center - Learners stretch bands around pegs to form line segments and polygons and make discoveries
about perimeter, area, angles, congruence, fractions, and more.
MathBoard Addition - Free, "addition only" version of MathBoard. Solve problems with a chalkboard area where problems can be worked.
OhNo!Fractions - practice and explore fractions visually. Answer if the fraction on the left is LESS, GREATER or EQUAL.
Sudoku - number strategy game.

Presentation:
Haiku Deck - Simple way to make slideshows.
Prezi for iPad - Create, edit, present, and share your prezis.
VoiceThread - create and share dynamic conversations around documents, snapshots, diagrams and videos. Have students add a text
comment or video an ASL comment.
ShowMe Interactive Whiteboard - Record what you are drawing and then share online or just play back.

Reference Materials: Students use various free reference materials to do assignments.
Atlas
Calculator Pro
Dictionary (dictionary.com)
Dictionary (Merriam-Webster)
FreeSaurus
Globe
Moon Globe

Science/Social Studies:
BrainPop Featured Movie - Watch a different animated movie every day, then test your knowledge with an interactive quiz. Has CC.
BrainPop Jr. Movie of the Week - Get a different animated movie every week and check out related quizzes and educational activities.
LabTimer (science) - count-up and alarming count-down multi-timer.
WeatherStation Free - Provides the official NOAA's real time weather information for the US location of your choice (except Alaska).

Tools:
i-nigma QR Code - turns your camera into a sophisticated barcode reader.
VisTimerFree - Free version of VisTimer. Max timer setting is 5 minutes. An animated shrinking pie chart shows elapsed time.
Popplet Lite - Brainstorming, diagraming, journaling type of app. Allows you to get down your thoughts quickly. Free version limited to 1
popplet/page.
Photo Explorer for Flickr Free - Browse, search and view your and public Flickr photos and videos.
ntouch - videophone app
P3 Mobile - videophone app

Board Games: Students practice turn taking, patience, hand-eye coordination, and other skills while playing a traditional game.
TicTacFree
UNO Free
4InRow:AKP
Checkers
Chinese Checkers
Bingo
FourInARowF
Memory!
RushHrFree
GuessCode
Barnyard MJF
Mahjong!!